Last thimble and process of making same



June 1 ,1926. 1,586,626

' G. J. JOHNSON L AST THIMBLE 4ND PROCESS OF MAKING SAME Filed Oct. 14, 1920 2 Sheets-Sheet l jZZQ/ 59 June 1 1926. 1,586,626 G. J. JOHNSON LAST THIMB'IJE'SAND PROCESS OF MAKING SAME Filed Oct. 14, 1920 2 Sheets-Sheet 2 Patented June i926.

vamp i sv'i aras- PATENT, OFFICE. 7

GUSTAV .1. aonnson, or MAnLBo'ao, alssleavsms, Assmnon r0 KoEHLER aimmcrmme commmz, or 'MARLBORO}MASSACHUSETTS, A. coaroaarxon or MASSACHUSETTS- ms; rename nn rnocnss or axine same.

s n anoaalea October '14. 1920. serial-n5. 416,965.

f As is well understood by those familiar with lasts, it is usual to insert a metallic thimbie in the conev of a last to receive the last spindle orjack spindle which is tosupport the last." Son-1e oft-hese thimbles are provided .with an out-turned flange that bears on the cone face of the last while others do not have this flange.

According to the process of manufacture usually practiced heretofore these thimbles have been made from circular blanks of metal by a punch and die process. That is, a'circular blank is first punched intothe form of acup-and-this cup is then drawn out by forcing it through aseries of diesdecrcasingsuccessively in diameter to produce a seamless tubular. thimble. When a flange is to be formed on the thimble several additional operations are required.

While this. process of manufacture has been practiced for many years, it s open to a'number of objections among which may be mentioned particularly,first, the fact that considerable waste metalnecessarily is pro duced in dieing out the circular blanks; second, it usually is necessary to anneal the stock after certain of the operations on'it to soften it sufliciently for the, next drawing operation; third, 'it is. necessary to pickle the partially formed thimbles between certain of the drawing operations to remove the scale; and fourth, this process produces a relatively large percentage of thimbles that are so defective as to be unsaleable.

. .A furtherdisadvantage of this process is' that it reduces to an undesirable degree the thickness of the wall of metal at the shoulder of the thimble; that is, the curve at the junctionof the walls and bottom of the thimble; That is due to the factthatthe maximum drawing action on the metal is exerted at this point and several of these drawing operations are required to produce a thimble bythis process. In making a flanged thimble it is nec'essaryto perform four of these drawing operations on each thimble and two annealing operations also.-are"requi-red. This thinning of the shoulder is particularly Ob. .jectionable since the greatest strain on the thimble when it is in use is exerted on-this shoulder and it isacommonexperience for thimbles to crack or Break at this point after onlya relatively brief period of use. The

' tion to improve the constructionand weakening a this Shams is due not any to the fact that. the wall of the thimble is thinner at this point than it should be, but also in some measure to the fact that the an nealing operations reduce the strength of the metal. i 7 It is the chief'object of the present invenprocesses of manufactureof last thimbles'with a view to overcoming the difliculties' and objections above described. In other words, the invention aims both to devise a construction'of last thimble which will be more substantial than those produced by prior processes and also to provide a process of manufacturing last thimbles which will reduce the manufacturingcost of these articles. I

The nature of the invention will be readily understood from the following description when read in connection with the accom pa'nyingdrawings, and the novel features pended claims. 7 y Referring nowto the drawings V Figure 1 is a plan view of a blank from whicha plain thimble is made;

Fig. 2 is an endelevat'on of the blank shown in Fig. 1; I Fig. 3 is an annular view showing a partly formed thimble after the first operation has been performed on the blank; 1 v V Fig. 4 is an angular view showing the finished thimble ;v

will be particularly pointed out in the ap- Fig. 5 is a plan View of a blank used in making a flanged thimble; Fig. 6 is an end view of in Fig. 5

Fig. 7

the blank shown is an angular view showing the first step in the formation of a thimble from the blank shown in Fig. 5;

Fig. 8 is an angular view illustrating the second step in this process; 7

, 'Figi 9 is an angular View completed thimble; and

' showing the Fig. 10 is a verticalcross sectional view through the'thimble shown in Fig. 9. r

. The drawings show the parts on a large scale for the purpose of illustrating the construction more clearly. The blank A,

Figs. 1 and 2,'from which a'plain thimble is made, is of approximately rectangular outline, the opposite ends 2-2, however, -be-' ing slightly curved convexly. "This blank is punched out of sheet metal of suitable thickness, say approximately one-sixteenth of an inch.

The blank A is next placed in a die of suitable shape, and a punchof the proper form to cooperate with this die acts on the central portion of the blank to force it through the die, thus folding the portions of the blank at opposite ends of its center upwardly at right angles to this central portion and simultaneously. curving'them toward each other into the form illustrated at B, Fig. 3. It will be seen that the blank now has been forced into a cup-like form having slots 33 in opposite sides thereof between the adjacent edges of the two side members 4 and 5. While the opposite ends .-?-2 of the blank A form the upper edge of the cup, this edge will be approximately square due to the fact that the stock draws more along the edges than it does at the central portion of the strip. t is because of this fact that the edges 22 of the blank are curved somewhat as shown in the drawings.

This partially formed thimble B is next forced through another die by a suitable punch, this die being smaller in diameter than the first one so that this operation results in drawing out the part B and closing up the slots 38. The result is the formation of the finished thimble C, Fig. 4. It will be observed that this thimble consists of a split tube with a cup-like bottom that joins the two halves 4: and 5 of the tube, these parts being separated by the scams 7 7.

When a flanged thimble is to be formed the first steps are similar to those in making a plain thimble. The blank, however, is preferably of a different shape as shown at D in Figs. 5 and 6. That is, this blank resembles the blank A in being of approximately rectangular outline and having convexly curved ends, but it differs from the blank A in being widened or flared somewhat at its ends, as clearly shown in the drawings. This flaring form is provided to furnish the stock for the flange. V

This blank is first punched through a die similar to that used to produce the member B which forces this blank into the form E, Fig. 7. This member like the member B is approximately cup-shaped with slots 99 at opposite sides thereof. This partially formed thimble is next punched throughanother die of suitable shape and size to close the slots 99 leaving simply a crack or seam 10 in each side of the thimble and bringing this thimble into the form F, Fig. 8. This punch and die are provided with suitably tapered parts which cooperate to flare the upper end portion of the thimble, as indicated at 12. The next operation turns this flared portion outwardly to form a flange 14, Fig. 9, and a fifth operation is required on this flange to trim off the edges,

thus forming the finished thimble G, Fig. 9.

The punch and dies required in performing successive steps of this process of manufacture have not been illustrated since the design or shape of these parts will be evident to those skilled in this art.

From the foregoing description it will now be seen that this process requires simply three steps or operations to produce a plain thimble and five operations to produce a flanged thimble. Either type of thimble, therefore, is produced with fewer punching operations than are required to produce the corresponding type of thimble by prior processes. Not only are these mechanical operations reduced in number by this process but it also avoids the necessity for annealing or pickling the thimbles at any stage in their process of n'ianufacture.

A further advantage produced by this invention is the fact that the shoulder. 15, Fig. 10, of the finished thimble is of substantially the same thickness as the walls of the thimble. That is, the excessive drawing of the stock at this point which, as above described, has been one of the objectionable features of prior processes, is avoided by the present process; and the fact that no annealing is required also prevents the additional weakening of the metal which otherwise would be produced. It has also been found by experience that the number of defective thimbles produced by this process of manufacture is substantially less than the percentage formed in prior processes. A very substantial saving also is effected in material since the blanks, being of approximately rectangular form, can be cut out of the sheet steel or'other stock with much less waste than can circular blanks.

What is claimed as new is V 1. A last thimble consisting of a split tube and a bottom integral with said tube and uniting the split members of the tube.

2. A last thimble consisting of a tube split longitudinally into two substantially equal parts and a cup-like bottom integral with said parts and uniting them.

3. That improvement in the process of making last thimbles which consists in forming a blank of substantially greater length than width acting on the central part of said blank to force it through a die of suitable shape to force said blank into a cnp-like form having slots in opposite sides thereof, and then repeating this operation with a smaller die to close said slots and draw out the walls of said cup-like member into a tubular shape.

4. That improvement in the process of making last thimbles which consists in forming a metal blank of approximately rectangular form having its ppposite ends convexly curved, punching said blank through a die of suitable shape to force said blank sides thereof and with the central part of the blank forming the bottom of said cup, and then repeating this operation with a smaller die to close said slots and draw out the walls of said cup-like member into a tubular shape. I

5. That improvement in the. process of making flanged last thimbles which consists blank to force it into a cup-like form having slots in opposite sides thereof, subsequently drawing out said cup-like member and clos- L- ing said slots, and then manipulating the upper end of the cup-likemember so produced to form an out-turned flange. I

6. That improvement in the process of making flanged last thimbles which consists in forming a metallic blankof approximately rectangular shape, punching said blank through a die of suitable shape to force the blank into a cup-like form having slots in opposite sides thereof and with the central part of the blank forming the bottom of said cup, next repeating this operation with "a smaller die to close up said slots 7 That improvement in the process of making flanged last thimbles which con-- sists in forming a metallic blank of approximately rectangular shape but having flaring ends, punching said blank through a die of in forming a. metallic blank of approX1-, matelyrectangular shape acting on said suitable shape to force the blank into a cup like form having slots in opposite sides thereof and with the central part of the blank forming the bottom of saidcup, next repeating this operation with a smaller die to close up said slots and simultaneously draw out the walls of; said cup-like member and flare its upper end, then turning said flaring partoutwardly to form a flange and finally trimming said flange.

8. A last thimble consisting of a single piece of'metal shaped to form a split tube and having a solid bottom integral with said tube, and an outturned top of said tube.

flange at the v In testimony whereof Ihave signed my ecification. USTAV J. JOHNSON.

name to this s 

